1. Field of the Invention
The present invention relates generally to wave generation, and in particular to a system for pneumatically generating waves in a pool of liquid.
2. Description of the Prior Art
Wave generation in liquids is well known and a variety of systems have heretofore been developed to satisfy the requirements of particular applications. For example, nautical engineers frequently use wave tanks in their design work to simulate sea conditions and study the performance of different hull designs in response to various simulated wave conditions.
Wave generators are also used in recreational applications, for example in swimming pools where mechanically-generated waves are provided to simulate conditions at oceanfront beaches. Swimming pools with wave-making equipment are quite popular, especially in amusement parks that feature a water theme. Depending upon the amplitude and configuration of the waves generated, a variety of activities are possible. For example, the Dexter U.S. Pat. No. 3,473,334 discloses an apparatus and method for producing waves of the spilling breaker type which are suitable for surfing. For normal amusement park operation, however, sinusoidal waves of lesser amplitude are preferred to accommodate bathers with various levels of swimming ability.
Various mechanical devices have heretofore been proposed with moving parts that engage and displace the water at one end of the pool to create a surface wave pattern. For example, movable pallets, swinging gates and immersed blocks have heretofore been employed and have been reciprocated in vertical, horizontal and inclined directions. However, such devices generally include mechanical equipment that is susceptible to rust and corrosion from chlorinated pool water.
The aforementioned Dexter U.S. Pat. No. 3,473,334 shows another type of wave-generating system wherein water is pumped from the pool into an adjoining compartment to a level above the quiescent water level in the pool. A subsurface gate is opened to release the elevated volume of water and generate a wave. However, gate mechanisms such as those shown in the Dexter patent can present construction, operation, corrosion and maintenance problems due to their complexity and the direct contact of their moving parts with the pool water.
Yet another disadvantage with mechanical devices that directly contact the water is that they tend to require relatively large amounts of force to displace sufficient volumes of water to generate useful waves. Furthermore, many such mechanical systems require oil, grease and hydraulic fluid, which can leak and contaminate the swimming pool water.
To avoid some of the aforementioned problems with mechanical wave generators, pneumatic/hydraulic systems have been devised. For example, the Herz U.S. Pat. No. 2,056,855 discloses a fan operated by an electric motor for blowing air into a caisson communicating with a swimming pool whereby waves are generated. Other pneumatic/hydraulic systems are shown in the Schuster et al. U.S. Pat. No. 3,629,877, and each includes a plurality of caissons in communication with a swimming pool. The caissons are pressurized by a plurality of motor-driven air blowers mounted above them. Each air blower is connected to a clapper valve for alternately pressurizing one of a pair of adjacent caissons. Sets of caissons are pressurized and depressurized with the clapper valves in alternating sequence so that a standing wave is formed and extends transversely across the pool, in addition to traveling waves that travel longitudinally through the pool.
Although the pneumatic/hydraulic systems shown in the Schuster et al. patent overcome many of the aforementioned difficulties with prior art wave generators, the Schuster et al. systems tend to be relatively expensive to install and operate since each requires a plurality of air blowers. The present invention addresses these shortcomings.